摘要
目的 探讨新生大鼠缺氧缺血性脑损伤 (HIBD)后脑内 μ calpain的活化、其他相关因子表达变化的时程及相互关系 ,进一步研究HIBD的发病机制。方法 HIBD模型采用改良的Rice法。应用Westernblot法半定量测定缺氧缺血 (HI)后 0、1、2、4、12和 2 4h大脑皮层和海马μ calpain、c Fos、c Jun、HSP70和HSP2 7的表达。蛋白浓度测定采用改良的Bradford法。结果 新生大鼠HI后 μ calpain裂解为 76和 80两个片段 ,两者比值在HI后显著提高 ,以海马更为明显 ,其中皮层在 2 4h、海马在 12h达到高峰。c Fos在HI后 2～ 12h海马显著高于皮层 (P <0 0 5 ) ,2 4h海马却低于皮层 (P <0 0 5 ) ;c Jun则 0～ 1h海马高于皮层 (P <0 0 5 ) ,4h以后皮层均高于海马 (P <0 0 5 ) (其中 12h差异无显著意义 )。c Fos和c Jun在HI后呈上升趋势 ,无论皮层或海马均在 2～ 4h达到高峰 ,以后渐下降 ,但 2 4h仍高于正常对照组。与对照组相比 ,c Fos在 1,2 ,4 ,12和 2 4h差异有显著意义 (P <0 0 5 ) ;c Jun在 0 ,1,2 ,4 ,12和 2 4h差异有显著意义 (P <0 0 5 )。HSP70在HI后 0h皮层显著高于海马 (P <0 0 5 ) ,1h海马显著高于皮层 (P <0 0 5 ) ,4h后皮层又均高于海马 (P <0 0 5 ) ;HSP2 7则HI后 1～ 2 4h海马均显著高于皮层 (P
Objective The cascade of physiological events underlying hypoxic ischemic brain damage (HIBD) remains to be fully established The perinatal brain shows both an increased tolerance to hypoxic ischemic (HI) injury and a faster and more complete recovery than the adult It is, therefore, important to understand the sequence of events following hypoxia and ischemia in young animals The present study aimed to clarify the time course of the activation of the μ calpain, and the expression of c Fos, c Jun, HSP70 and HSP27 proteins following severe HI ( 2 h hypoxia ) and their relationship with each other Methods A modified newborn rat model of HIBD that included a combination of hypoxia and ischemia as described by Rice was used Forty two postnatal 7 day old Sprague Dawley rats were randomly divided into seven groups (6 rats in each): 6 time window groups and a normal control group Samples were collected at 0, 1, 2, 4, 12 and 24 h after HI insults The protein concentration was determined using a modified Bradford assay μ calpain activation, c Fos, c Jun, HSP70 and HSP27 expressions were observed respectively by Western blot from cortical and hippocampal samples Results The cleavage of cytosolic μ calpain was observed from both cortical and hippocampal samples in neonatal rats after HI The ratio 76∶80 of μ calpain was increased significantly post HI and reached a maximum at 24 h in cortex and at 12 h in hippocampus after HI The expressions of c Fos and c Jun from both cortical and hippocampal samples in neonatal rats were up regulated and peaked at 2 or 4 h after HI, demonstrating significant differences at 1, 2, 4, and 12 h compared with that observed in the control ( P <0 05) When compared with that observed in cortex, the nuclear c Fos expression from hippocampal samples was highly elevated at 2, 4 and 12 h but significantly decreased at 24 h after HI ( P <0 05), while the nuclear c Jun expression from hippocampal samples was highly elevated at 0 and 1 h
出处
《中华儿科杂志》
CAS
CSCD
北大核心
2004年第6期441-445,共5页
Chinese Journal of Pediatrics
